ESP8266 Community Forum

Posted: **Fri Sep 16, 2016 6:57 pm**

I can't et any communication between my Arduino Uno and an ESP01.
Everything is wired up correctly (including a seperate 3.3v supply for the esp).

For testing, I've written this code:

Code: Select all

#include <SoftwareSerial.h>

SoftwareSerial mySerial(10, 11); // RX, TX
long int boud_rate_array[] = {1200,2400,4800,9600,19200,38400,57600,115200,230400};


void setup() {
  Serial.begin(9600); 
  while (!Serial);
  Serial.println("Start test");
}
void loop() { 
    for (int i = 0; i<9;i++){
      
      Serial.println("baud rate: ");
      Serial.println(boud_rate_array[i]);
      Serial.println("send AT command");
      mySerial.begin(boud_rate_array[i]);
      mySerial.println("AT");
      delay(2000);
      while (mySerial.available()){
     String inData = mySerial.readStringUntil('\n');
     Serial.println("Got reponse from ESP8266: " + inData);
  }
      delay(5000);
      
      
    }
  }

And this is the result of it:

Code: Select all

Start test
baud rate: 
1200
send AT command
Got reponse from ESP8266: ÿÿÿÿ
baud rate: 
2400
send AT command
Got reponse from ESP8266: ÿÿÿÿ
baud rate: 
4800
send AT command
Got reponse from ESP8266: ÿÿÿÿ
baud rate: 
9600
send AT command
Got reponse from ESP8266: ÿüÿþ
baud rate: 
19200
send AT command
Got reponse from ESP8266: –þñ
baud rate: 
38400
send AT command
Got reponse from ESP8266: I›þ
baud rate: 
57600
send AT command
Got reponse from ESP8266: )Ò$þ
baud rate: 
115200
send AT command
Got reponse from ESP8266: ¡µÔE¶5‚
baud rate: 
230400
send AT command
baud rate: 
1200
send AT command
Got reponse from ESP8266: ÿÿÿÿ
baud rate: 
2400
send AT command

As you can see, only gibberish.
What am I doing wrong? I hope someone can help me

When connecting to ports 0 & 1, it works fine (so, there should be an issue with the serialsoftware connection but I cant find what it is).

Thx,
Peter

Posted: **Sun Sep 18, 2016 10:39 pm**

Interesting method to find the baud rate. depending on the uC speed (8mhz,16mhz,etc) the Software serial has limitations. I know at 8Mhz 115200 will not function. Otherwise, try to send AT+CIOBAUD=9600 to change it to a known 9600. But you will need to send it using the baud rate of the ESP module (usually 115200).

Posted: **Mon Sep 19, 2016 7:04 am**

Hello .
I have seing some esp , that the tx rx are inverted .
insted of
rx >>> tx
tx >>> rx
try out
rx>>> rx
tx>>> tx

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